This is similar to some other cam mounts for C920, but with the camera further out to the right of the printer, to avoid the carriage from hitting the camera (happens with some fanmod parts) and to give better focus when the nozzle prints further to the right.  The camera rides up and down with the nozzle to keep an optimum view.

There's also a version for if you want to mount the webcam higher from the top of the extruder bar.

Easy and fast print, mount to the printer with a couple sets of screws and nuts (various sizes will work).  Will need the right bolt or knob to mount the camera to it, matching the thread for on the camera – if you don't have one already, included here is also a nice knurled bolt for the purpose.